The history of our planet has been written, among other things, in the periodic reversal of its magnetic poles. Scientists at the Weizmann Institute of Science propose a new means of reading this historic record: in ice.
ادامه مطلب
Here, we report magnetic properties of iron minerals formed by a community of iron- and manganese-reducing bacteria isolated from a natural groundwater deposit during a 2 yr long incubation experiment. The main iron phases of the biomineralized mass are lepidocrocite, goethite and magnetite, each of which has environmental significance.
ادامه مطلب
The origin of natural magnetic minerals present in soils can be lithogenic (primary) and pedogenic (secondary). Lithogenic magnetic minerals are usually coarse-grained and inherited from the parent rock.
ادامه مطلب
These rocks contain tiny crystals of a hardy mineral called zircon, which are chips off an even older block: 4.2-billion-year-old Hadean rocks that formed from cooling …
ادامه مطلب
Mineral Magnetism: Providing New Insights into Geoscience Processes. Magnetic minerals are ubiquitous in the natural environment, and they are also present in a wide …
ادامه مطلب
Competing ideas suggest how sloshing motions could maintain a primordial magnetic field. ... Each relies on minerals crystallizing out of the molten Earth, a process that would have generated a ...
ادامه مطلب
But a new technique reported this week in Nature may help narrow things down. Gathering material from six fire pits, all dating to roughly 52,000 years ago, …
ادامه مطلب
The vortex-like structures in grains of magnetite can reliably preserve magnetic information, remaining unaltered by temperature changes, thereby recording the history of the Earth's magnetic field. That is the latest finding of researchers in Germany and the UK, who used electron holography to map the magnetic properties of individual …
ادامه مطلب
Natural History Magazine. advertisement. Departments. Features; Samplings; Nature; Bookshelf; Skylog; Biomechanics; ... Where to find Natural History archives and other …
ادامه مطلب
Each year, Smithsonian scientists collect hundreds of meteorites from Antarctica that reveal details about the origins of Earth and our solar system.
ادامه مطلب
v5n4 Mineral Magnetism: From Microbes to Meteorites. Guest editor: Joshua M. Feinberg (University of Minnesota) and Richard J. Harrison (University of Cambridge) Magnetic minerals are ubiquitous in the natural environment.
ادامه مطلب
Iron, the pre-eminent seat of magnetism in natural minerals (Section 2.2.4), is the fourth most abundant element in the Earth's crust. Consequently it is an important constituent of the majority of rocks found at the Earth's surface.
ادامه مطلب
Each relies on minerals crystallizing out of the molten Earth, a process that would have generated a magnetic field by churning the young planet's iron core.
ادامه مطلب
Magnetic nanovortices in magnetite minerals are reliable witnesses of the Earth's history, as revealed by the first high-resolution studies of these structures undertaken by scientists from ...
ادامه مطلب
In general, the strength of mineral repulsion by magnetic field is very weak. Therefore, in the identification, separation and general research of minerals, the magnetic properties mainly refer to the properties of minerals attracted by the external magnetic field. Why are magnetic minerals important to natural history?
ادامه مطلب
Since the 1970s, ferromagnetic minerals were believed to be absent in the Earth's mantle and, even if present, the temperatures were considered too high for such phases to carry magnetic remanence.
ادامه مطلب
A magazine of science, nature, and culture. The Web site includes selections from the current issue, editors' Picks from the Past, Natural History's blog, and information for subscribers and advertisers.
ادامه مطلب
Trapped inside about two dozen zircons were even tinier grains of an iron-containing mineral, magnetite, that effectively turned each crystal into a miniscule bar magnet. The researchers found that the magnetic fields held by the grains were all aligned, which occurs only if magnetite is exposed to a magnetic field as it cools.
ادامه مطلب
Oceanic deoxygenation began about one million years earlier than the marine End-Permian mass extinction, as indicated by variations in magnetic mineral assemblages and geochemical anomalies.
ادامه مطلب
Regardless of their origin, these minerals become aligned with Earth's ambient magnetic field before they are fixed within a speleothem's growing carbonate matrix. Here, we describe how the magnetism of stalagmites and flowstone can be used to chronicle high-resolution geomagnetic behavior and environmental change.
ادامه مطلب
Magnetic nanovortices in magnetite minerals are reliable witnesses of the Earth's history, as revealed by the first high-resolution studies of these structures …
ادامه مطلب
The magnetic needle of a compass lines up with Earth's magnetic poles. The north end of a magnet points toward the North Magnetic Pole, which holds a south magnetic charge. ... These chunks of iron-rich minerals may have been magnetized by lightning. The Chinese discovered that they could make a needle magnetic by stroking …
ادامه مطلب
The iron is released from the clay minerals and provides the reducing agent, while Al decreases the crystallinity of haematite and thus facilitates the chemical reaction. Therefore, the thermal magnetic measurements can be used to quantify the Al content of Al-hm in natural samples.
ادامه مطلب
Iron and oxygen can join in a variety of ways to form compounds, so we get different iron minerals, magnetic magnetite and non-magnetic hematite, siderite ad infinitum and even rust. What are Iron Minerals? – Magnetite. Most mineral collectors are familiar with minerals centered on iron-like magnetite, a natural magnet.
ادامه مطلب
Rocks have a magneticmemory that may endure for millions or even billions of years. The secret behind that longevity lies in the high temperatures to which the minerals were exposed—near their Curie temperatures of several hundred degrees Celsius—while cooling in Earth's magnetic field and in the stabilizing influence of the cooling process …
ادامه مطلب
The preferred "handedness" of biomolecules could have emerged from interactions between electrons and magnetic surfaces on primordial Earth, new research …
ادامه مطلب
It may be surprising to many, but your brain is full of magnetic minerals. That's right: Buried in your brain right now are clumps of magnetite, a mineral composed of iron oxide that is ...
ادامه مطلب
Some minerals and rocks possess fascinating magnetic properties, crucial for geologists and paleontologists and those curious about their own mineral collections. Minerals like magnetite, pyrrhotite, …
ادامه مطلب
Magnetic Magazine is a leading online publication focused on music, record labels, offering interviews & industry news. Explore the latest trends today!
ادامه مطلب
Ancient scientists discover the magnetic effect in natural magnetite minerals as early as 600-400BC. In the 12 th century, the compass is used by many Chinese sailors Hans Christian Oersted discovers in 1820 rather accidentally, that the flow of electric current influences the needle of a compass.
ادامه مطلب
The most magnetic and common type is a lodestone. It consists of a brownish-black mineral called magnetite. Lodestones are natural compasses: Suspend one by a thread or wire and it will rotate until its magnetic field is aligned with Earth's magnetic field. A magnetic field is the area around a material in which its magnetic …
ادامه مطلب
Subscribe to Natural History Magazine; Give a gift subscription; Recent Stories. Salmon. The way they live, the food they eat, and the effect on us. The Story of Gosling Sandhill. A true but unlikely tale. Story and Photographs by William Rowan. Oxygenation Stutter Steps.
ادامه مطلب
We now report downcore magnetic profiles from undisturbed Kasten cores taken in rapidly deposited laminated sediments from the Gulf of California and in bioturbated haemipelagic muds on the Oregon ...
ادامه مطلب